In recent years, a modulation method called orthogonal frequency division multiplexing (OFDM) is employed as a method for transmitting digital signals. The OFDM method is a method of providing a large number of orthogonal subcarriers in a transmission band, allocating data to amplitudes and phases of the respective subcarriers, and digitally modulating a signal according to the PSK (phase shift keying) and the QAM (quadrature amplitude modulation).
The OFDM method is often applied to the terrestrial digital broadcasting that is intensely affected by multipath interference. Examples of the digital terrestrial broadcasting employing the OFDM method include standards such as the DVB-T (digital video broadcasting-terrestrial) and the ISDB-T (integrated services digital broadcasting-terrestrial).
In the meantime, the DVB (digital video broadcasting)-T.2 is being established as a standard for next-generation digital terrestrial broadcasting by the ETSI (European Telecommunication Standard Institute) (see Non-Patent Document 1).